Hubungan Antara Besar Butir dengan Kekuatan dan Kekerasan pada Aluminium Paduan Berbutir Kasar

Harsono Wirjosumarto, Rudy Setyo Purnomo

Abstract


Sari. Hubungan Hall-Petch, σt = σi + KD-1/2 diteliti kembali dengan menggunakan aluminium paduan berbutir kasar, besar butir antara 0,069mm dan 0,404 mm, sebagai bahan uji. Hasil penelitian menunjukkan bahwa harga konstanta K dari perhitungan teoritik dan dari percobaan mempunyai kesesuaian yang tinggi, yaitu perhitungan teoritik K = 0,0514 dan percobaan K = 0,052; tetapi harga eksponen dari percobaan bukannya -0,5 melainkan -1,86. Hubungan antara kekerasan dan kekuatan hasil percobaan sesuai dengan hasil perhitungan teoritik, yaitu hubungan garis lurus dengan konstanta hasil percobaan C = 0,335 sedangkan perhitungan teoritik C = 0,35 ÷ 0,39. Dengan hasil ini hubungan tersebut untuk aluminium menjadi σt = 0.335 BHN. Butir-butir aluminium yang berlainan besarnya dihasilkan dengan cara regang-anil dengan merubah temperature anil pada harga regang dan waktu anil yang sama.

 

Abstract. Hall-Petch relation, σt = σi + KD-1/2, is re-examined and tested to a coarse grain aluminum alloy with grain size between 0.069 mm and 0.404 mm. The result indicates that the theoretical and experimental value of K match each other closely, i.e. Kth = 0.0514 and Kexp = 0.052. 0n the other hand the experimental value of the exponent is -1.86 instead of -0.5. The experimental relation between hardness number and strength matches reasonably well to the theoretical analysis, which is linear. The experimental value of the linearity constant is Cexp = 0.335 and the theoretical constant is Cth= 0.35 ÷ 0.39, therefore this aluminum alloy the relation is σt = 0.335 BHN. The grain size difference of the specimen was obtained by strain-annealed method by varying the annealing temperature at constant strain and annealing time.


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References


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